general cleanup - removed old comments, enforced naming conventions etc

backend/internal/protocols/ethereum/observer.go

@@ -0,0 +1,16 @@
+package ethereum
+
+import (
+	"context"
+
+	"github.com/kjannette/koin-ping/backend/internal/domain"
+)
+
+// EthereumObserver defines the interface for blockchain interaction.
+// Any concrete implementation (JSON-RPC, WebSocket, mock) must satisfy this.
+type EthereumObserver interface {
+	GetLatestBlockNumber(ctx context.Context) (int, error)
+	GetBlockTransactions(ctx context.Context, blockNumber int) ([]domain.NormalizedTx, error)
+	GetBalance(ctx context.Context, address string) (string, error)
+	GetTokenTransfers(ctx context.Context, fromBlock, toBlock int, address string) ([]domain.NormalizedTx, error)
+}